Official YouTube thumbnail specs in 2026
YouTube's documented thumbnail requirements: 1280×720 pixels minimum (720p), 16:9 aspect ratio, under 2MB file size, JPG/GIF/PNG format. The 16:9 ratio is mandatory — non-16:9 images get auto-cropped with black bars or stretched into distortion.
Upload at 1920×1080 (still 16:9) if you have the source resolution — YouTube downsamples to display sizes, and a higher-res master future-proofs as YouTube rolls out 4K thumbs to TV screens. The resizer above outputs at 1280×720 by default and offers 1920×1080 if your source supports it.
